diff --git a/lib/CLI.js b/lib/CLI.js
index de98e9bb..bab6bb58 100644
--- a/lib/CLI.js
+++ b/lib/CLI.js
@@ -286,11 +286,32 @@ CLI.actionFromJson = function(action, file, jsonVia, cb) {
   });
 };
 
+/**
+ * Extend the app.env object of with the properties taken from the app.env_[envName].
+ * @param {object} app The app object.
+ * @param {string} envName The given environment name.
+ * @returns {object} The app.env variables object.
+ */
+function mergeEnvironmentVariables(app, envName) {
+  app.env = app.env || {};
+  if (envName && 'env_' + envName in app) {
+    /**
+     * Merge specific environment variables
+     * `--env production` will merge `env_production` with the env
+     */
+    util._extend(app.env, app['env_' + envName]);
+  }
+
+  return app.env;
+}
+
 /**
  * Process and start a JSON file
  * @method startJson
  * @param {string} cmd
+ * @param {object} opts
  * @param {string} jsonVia
+ * @param {function} cb
  */
 CLI.startJson = function(cmd, opts, jsonVia, cb) {
   var appConf;
@@ -310,19 +331,10 @@ CLI.startJson = function(cmd, opts, jsonVia, cb) {
     return exitCli(cst.ERROR_EXIT);
 
   async.eachLimit(appConf, cst.CONCURRENT_ACTIONS, function(app, next) {
+    mergeEnvironmentVariables(app, opts.env);
     try {
-      if (opts.env) {
-        /**
-         * Merge specific environment variables
-         * `--env production` will merge `production_env` with the env
-         * -> for pm2-deploy
-         */
-        app.env = app.env || {};
-        util._extend(app.env, app['env_' + opts.env]);
-      }
-
-      var app_paths = resolvePaths(app);
-    } catch(e) {
+      resolvePaths(app);
+    } catch (e) {
       debug(e.stack || e);
       return next();
     }
@@ -796,20 +808,12 @@ CLI._jsonStartOrAction = function(action, json_conf, opts, cb) {
     });
 
     async.eachLimit(apps_to_start, cst.CONCURRENT_ACTIONS, function(app, next) {
+      mergeEnvironmentVariables(app, opts.env);
       try {
-        if (opts.env) {
-          /**
-           * Merge specific environment variables
-           * `--env production` will merge `production_env` with the env
-           */
-          app.env = app.env || {};
-          util._extend(app.env, app['env_' + opts.env]);
-        }
-
-        var resolved_paths = resolvePaths(app);
-      } catch(e) {
+        resolvePaths(app);
+      } catch (e) {
         printError(e);
-        return cb ? cb({msg : 'Error'}) : exitCli(cst.ERROR_EXIT);
+        return cb ? cb({msg : e.message || e}) : exitCli(cst.ERROR_EXIT);
       }
 
       Satan.executeRemote('prepare', resolved_paths, function(err, data) {
@@ -858,7 +862,7 @@ CLI._jsonStartOrAction = function(action, json_conf, opts, cb) {
           async.filter(appConf, function(app, callback){ callback(app.name == proc.name); }, function(apps){
             var envs = apps.map(function(app){
               // Binds env_diff to env and returns it.
-              return util._extend(app.env || {}, opts.env && ('env_' + opts.env in app) ? app['env_' + opts.env] : {});
+              return mergeEnvironmentVariables(app, opts.env);
             });
             // Assigns own enumerable properties of all
             // Notice: if people use the same name in different apps,
@@ -1570,7 +1574,7 @@ function verifyConfs(appConfs){
  * @param {Object} conf
  */
 function checkExecMode(conf) {
-  
+
   if (conf.exec_mode === 'cluster' ||
       conf.exec_mode === 'cluster_mode' ||
       conf.instances && conf.exec_mode === undefined)
@@ -1591,7 +1595,7 @@ function checkExecMode(conf) {
 
   if (conf.instances && conf.exec_mode === undefined)
     conf.exec_mode = 'cluster_mode';
-    
+
   //process.version.match(/0.10/) &&
   // Tell user about unstability of cluster module + Roadmap
   if (/^cluster(_mode)?$/i.test(conf.exec_mode) &&